I propose to continue our research on the regulation of gene activity in eukaryotic cells using Dictyostelium as an experimental system. Recombinant plasmids carrying the presumptive gene sequence for actin and several other developmentally regulated proteins have been isolated. These will be used to ask questions on the rate of synthesis and turnover of mRNA, gene structure and its relation to possible control mechanisms, and nuclear precursors and their processing. The analysis of the expression of these specific genes will be approached with the future goal to understand the control mechanisms involved during differentiation in eukaryotes.